UMC (NYSE: UMC) vice president discloses direct and indirect share stakes

Rhea-AI Filing Summary

UNITED MICROELECTRONICS CORP vice president Yu-Chih Chuang filed an initial Form 3 reporting beneficial ownership of company shares. The filing shows direct ownership of 1,199,331 common shares and indirect ownership of 13,943 common shares held by a spouse.

A footnote explains that these holdings include 674,600 shares of Restricted Stock Awards. Specified portions of this restricted stock are scheduled to vest each year on December 5 from 2026 through 2029, illustrating a multi‑year equity compensation structure tied to continued service.

Insider Trade Summary

2 transactions reported

Mixed 2 txns

Insider CHUANG YU-CHIH

Role Vice President

Type	Security	Shares	Price	Value
holding	Common Shares	--	--	--
holding	Common Shares	--	--	--

Holdings After Transaction: Common Shares — 1,199,331 shares (Direct, null); Common Shares — 13,943 shares (Indirect, By Spouse)

Footnotes (1)

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Key Figures

Direct common share holdings: 1,199,331 shares Indirect common share holdings: 13,943 shares Restricted Stock Awards: 674,600 shares

3 metrics

Direct common share holdings 1,199,331 shares Directly owned UMC common shares reported on Form 3

Indirect common share holdings 13,943 shares UMC common shares held indirectly by spouse

Restricted Stock Awards 674,600 shares RSA shares included in holdings, vesting annually on December 5 from 2026-2029

Key Terms

Restricted Stock Award (RSA), indirect ownership, Common Shares

3 terms

Restricted Stock Award (RSA) financial

"Includes 674,600 shares of Restricted Stock Award (RSA) and a specified number"

indirect ownership financial

"total_shares_following_transaction: 13943.0000, direct_or_indirect: I, nature_of_ownership: By Spouse"

Common Shares financial

"security_title: Common Shares, transaction_type: holding"

Common shares are the basic units of ownership in a company that give holders a claim on profits and a right to vote on key matters, like electing the board. Think of them as membership cards in a club: they let you share in successes and losses, but in a bankruptcy or liquidation they are paid after creditors and preferred shareholders, so their value can swing more and matters for assessing risk and potential return.

Understanding Insider Trading Forms →

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

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1. Name and Address of Reporting Person^*

CHUANG YU-CHIH

(Last) (First) (Middle)

8F, NO.68, SEC. 1, NEIHU RD.,

(Street)

TAIPEI TAIWAN 11493

(City) (State) (Zip)

TAIWAN

(Country)

2. Date of Event Requiring Statement (Month/Day/Year)
04/29/2026

3. Issuer Name and Ticker or Trading Symbol
UNITED MICROELECTRONICS CORP [ UMC ]

3a. Foreign Trading Symbol
[2303.TW]

5. If Amendment, Date of Original Filed (Month/Day/Year)

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Vice President

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Shares	1,199,331(1)	D
Common Shares	13,943	I	By Spouse

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Includes 674,600 shares of Restricted Stock Award (RSA) and a specified number of shares subject to the RSA will vest annually on December 5 from 2026 to 2029.

Remarks:

Exhibit List Exhibit 24: Power of Attorney

	/s/Chitung Liu, attorney-in-fact	05/07/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 3: SEC 1473 (03-26)

FAQ

What does the UMC (UMC) Form 3 filing by Yu-Chih Chuang disclose?

The Form 3 shows Yu-Chih Chuang’s initial beneficial ownership in UMC. It reports 1,199,331 common shares held directly, 13,943 common shares held indirectly through a spouse, and notes that the reported holdings include 674,600 Restricted Stock Award shares vesting over several years.

How many UMC common shares does Yu-Chih Chuang directly own?

The filing reports direct ownership of 1,199,331 UMC common shares. This figure represents Chuang’s direct beneficial stake, separate from any indirect holdings, and serves as the baseline ownership position disclosed in this initial Form 3 for United Microelectronics Corp’s vice president.

What indirect UMC shareholdings are reported for Yu-Chih Chuang?

The Form 3 reports 13,943 UMC common shares held indirectly by Yu-Chih Chuang through a spouse. Indirect ownership indicates beneficial interest where another person, such as a family member, is the registered holder, but the executive is still considered to have a reportable economic stake.

What are the 674,600 Restricted Stock Awards mentioned in the UMC filing?

The footnote states that 674,600 shares are Restricted Stock Awards included in the reported holdings. Portions of these awards will vest annually on December 5 from 2026 to 2029, meaning the shares become fully owned over time as vesting conditions are satisfied.

Does the UMC Form 3 show any insider buying or selling activity?

The Form 3 functions as an initial ownership report and does not show explicit buy or sell transactions. Instead, it lists Chuang’s direct and indirect common share holdings and the presence of Restricted Stock Awards, establishing a starting point for future Form 4 transaction reporting.